The applicant's prior filed international application PCT/AU98/00834 describes in detail the problems associated with firstly starting a screw hole through a hard surface with a drilling tool, and then driving a screw which is inserted into the start hole, with a screw driver. Generally two different tools are required for the two different operations and this significantly increases the time required to insert the screw into the surface.
Modern electric power tools can be rotated at speeds which vary between very low speeds, as may be used to drive a screw, and very high speeds which are used for drilling holes and surfaces.